Science writer and journalist

Menu

Superbugs are on the rise in Canada, but not as fast as WHO suggests

Drug resistant gonorrhea under a microscope.PHOTO: THE CANADIAN PRES/PUBLIC HEALTH ONTARIO

Published: May 1, 2014

A World Health Organization report on superbugs suggests Canada has one of highest rates of drug resistant gonorrhea in the world.

But Canadian health officials say they have no idea where the international agency got the data indicating 31 per cent of the microbes causing the sexually transmitted disease in Canada show resistance to third-generation cephalosporins, an antibiotic of last resort.

“We just don’t know where they pulled that number from,” says Michael Mulvey, who tracks resistant organisms for the Public Health Agency of Canada.

The cephalosporin resistance rate for gonorrhea in Canada is 5.9 per cent, says Mulvey, chief of antimicrobial resistance and nosocomial (hospital acquired) infections at Canada’s National Microbiology Laboratory in Winnipeg.

More than 3,000 samples of neisseria gonorrhoeae, the bacteria that causes gonorrhea, are tested annually as part of a national surveillance program. Mulvey says there was a slight drop in cephalosporin resistance in 2012, down from 7.6 per cent in 2011.

The WHO report released Wednesday includes a chart showing 31 per cent Neisseria gonorrhoeae bacteria tested in Canada had reduced susceptibility to cephalosporin, second only to Slovakia and Slovenia at 37 per cent.

Gonorrhea can lead to infertility, throat and rectal infections and blindness in infants born to infected mothers. The Canadian Public Health Agency reports there were 12,561 cases of gonorrhea in Canada in 2012 up from 11,397 cases in 2011.

While Canada’s gonorrhea cephalosporin resistance rate is six per cent not 31 per cent, Mulvey said Thursday, it is a worry.

“We are very concerned with cephalosporin resistance in gonorrhea because there are very limited numbers of drugs left,” Mulvey said. Doctors are now trying “combinational therapy” using two types of antibiotics to hit the organism and stop infections, he says.

While the WHO gonorrhea numbers may be suspect, Mulvey says the report is correct about Canada’s increasing rates of resistance in E. Coli, a common bacteria associated with blood, lung, skin and urinary infections.

The report says tests on E. coli from 646 patients in Canadian hospitals found 26.9 per cent of the bacteria were resistant to fluoroquinolones, one of the most widely used antibacterial medicines for treating infections.

“In the 1980s, when these drugs were first introduced, resistance was virtually zero,” the report says.

While Canada’s 27 per cent resistant rate is a concern, it is much higher in many countries. “Today, there are countries in many parts of the world where this treatment is now ineffective in more than half of patients,” the report says.

E. Coli resistance to third-generation cephalosporins – considered drugs of last resort – is also on the rise around the world. In Canada, more than six per cent of the 646 E. Coli samples tested showed resistance to these drugs. The Canadian E. Coli data in the WHO report was collected by a team lead by Dr. George Zhanel, an infectious disease specialist at the University of Manitoba, who works in collaboration with the PHAC to test microbe samples collected at 15 hospitals across the country.

It’s estimated antibiotic resistant bacteria kill about 2,000 Canadians a year and sicken thousands — numbers soon expected to climb due to the rise of ever-more resistant bacteria that are increasingly difficult to kill.

Carbapenem resistant enterobacteriaceae, or CRE, are the most alarming resistant organisms. These so-called “nightmare” bacteria have the biochemical machinery to withstand nearly all antibiotics on the shelf. They also readily share their genes for resistance with other bacteria.

While still rare in Canada, CRE have shown up in Ontario, Quebec, Alberta and, most recently, caused an outbreak in B.C. Mulvey says 219 CRE infections were reported across Canada in 2013, up from just five cases in 2008 when they first seen in this country.

He says Canada’s CRE rate is still very low compared to other countries, such as India, where the multi-drug resistant organisms are now common. “We’ve just started to see it,” says Mulvey. “It’s a definitely a concern and we are monitoring it closely.”